CVE 2006-7230
Perl-Compatible Regular Expression (PCRE) library before 7.0 does not properly calculate the amount of memory needed for a compiled regular expression pattern when the (1) -x or (2) -i UTF-8 options change within the pattern, which allows context-dependent attackers to cause a denial of service (PCRE or glibc crash) via crafted regular expressions.
See the 
CVE page on Mitre.org
for more details.
